Elastic bit breaker



Dec. 31, 1940. J. A. ZUBLIN 2,227,208

ELASTIC BIT BREAKER Filed June 26, 1959 INVENTOR JOHN A. ZUBLIN a bit."

' Patented Dec. 31, 1940 UNITED STATES PATENT OFFICE nms'rro BIT BREAKER; John A. Zublin, Los Angeles, cam. Application June 26, 1939, Serial No. 281,104

This invention relates to the drilling of wells,..

more particularly, to rotarydrilling.

Modern drilling is accomplished by a bit fastened to a drill collar, the collar suspended from a string of drill pipe which extends to the surface. Changing the bit, necessitated by the wear thereon incident to use, is accomplished by raising. the drill pipe and drill collar to above the rotary table, and securing the bit to the table against rotation with respect to the table, and

using tongs upon the drill collar, to break or tighten the joint between the collar and the bit. When the collar is loose enough to turn, it is spun by a rope or the rotary table turned to drive the bit about;

When the drill collar is first placed over the bit, it is lowered by letting down the elevators, and the weight oi the drill collar allowed to rest upon the pin of the bit, after which the bit and collar are rotated with respect to each other until the joint is set up. In, this lowering, ex-

treme care is necessary on the part of the driller to ensure that the collar does not come down upon the bit too hard, for the bit is rigidly supported and the mass of the collar so great that .thethreads of the jointwould be subject to deforming stresses if the collar were to engage them at any speed. The hook holding the elevator has a spring in it, for the purpose of lifting the stands of drill pipe as they disengage on breaking the tool-joints.

and to permit easy assembly of drill pipe in the trip into the hole, but such spring is ineflective in action upon the drill collars, as the collars are 85 so heavy that the spring, designed for stands of drill pipe, is ineflective, the load being taken without springing whenit' is much greater than the 'weight of a stand-of pipe.

. Much damage to threadsresults from the pol 4o lar hitting the threads of the pin eccentricitlly,

eitherv thelo'utside surface of the collar or the interior oi?- .the threaded box. The ordinary breaker supportsethe bit more or less rigidly, the

teethof the bit biting into the metal-o! the bot- I tomo! the breaker and preventing the bit from moving radially when the pin is subject to'radial impacts.

are not intended to withstand impact loads as the collar engages the bit, andare therefore. some- "50 times 'broken while "making" up the bit on the "drillcollarp It thereioi'ah comes. a primary object of my invention to} protect thegthreads of the bit and 'Ldrill collar as the collar is engaged with the Further, the cutter teeth of the bit.

It is a further object of my invention to provide means for the protection of the teeth of the bit cutter as it is placed in the breaker and as the collar is stabbed onto the bit. I

It is a further object of my invention to pto-' vide means for permitting the threads to engage as the bit and collar are rotated relatively to each other, which will ensure movement of the bit sufiiciently to engage the threads. Briefly. what I propose to do is to provide a breaker with a cushioning element, to engage the bottom of the bit, and of sufficient resiliency to give under the combined weights of the bit and collar, and force the bit upwardly into the collar when the collar in turning rea'chesthe proper position for engagement of the threads.

I furtherintend to provide suflicient resiliency radially oi the bit pin to permit it to give under impact loads sideways of the pin.

In the drawing:

Figure 1 is. a general view 01' my improved breaker in use, partly in section; and r 're 2 is a perspective view or the top of my improved breaker. v

Referring to the drawing, the: bit breaker in is of a generally basket shaped configuration,

' with a top H to fit the square recess in the rotary table which normally holds the kelly bushing. The top of the breaker is provided with an opening l3, 0! such a shape as to permit entry of the bit, but to prevent rotationof the bit in the breaker.

Fastened below the top II is the [receptacle ll, generally tapered, in usual practice, to clear the tapered opening in the rotary which takes the slips.

Mounted in the receptacle is a cushioning, elea ment I 2, of rubber, for example, or a spring assembly, or any other suitable cushioning means for engaging the bit as it is lowered into the breaker. This cushioning element is capable of horizontal as well as vertical movement, so that under influence of eccentric vloads, or impacts on the sides of the pin of the bit, the bit will pivot about the edge of the opening it to-cushion the blow, and not ofler a rigid resistance to impact.

tending to damage the threads, and, incidentallm protecting the teeth of the cutters from damage tending to split oh the hard facing of the teeth.

In Figure 1 I have illustrated my breaker in 5 2 collar l8 lowered by the hook l9 and the elevator 20 into engagement, as is the usual practice.

However, instead of depending upon the spring.

(not shown) usually present within the swivel mechanism of the hook, to protect the threads as the collar engages them, and to force the threads into engagement, the cushion I2 is used to perform these functions. This change makes it possible for the driller to assemble the bit and collar more readily, as he can lower the collar until the joint engages, much more rapidly than would be safe if the bit were solidly supported. The cushion then supports. some of the weight of the collar, and the bit sinks into the cushion. Upon-relative rotation or the bit and collar, either by turning the table or by spinningthe collar, the threads will come to the proper position to engage, and the bit will snap upwards, and continued rotation will screw the bit onto the collar. inasmuch as there is no movement of the heavy drill collar in an axial direction which is necessary for the engagement ;of the threads, not only is the impact or the. collar threads on the bit threads minimized when the collar is lowered over the bit, but also there is-no heavy load imposed when the bit snaps up when the threads are in proper angular relation for screwing together.

In view of the fact that the cushion-is never called upon to support more than an impactload of the drill collar on the bit, it can be made quite soft, comparatively speaking. Since the bit is of considerably lower mass than the drill collar, the mass of the drill collar is ineflective in damaging the threads upon impact, which also saves the threads.

v It is to be understood that the shown form is not limitative, but illustrative only. The cushion shown need not be in the basket, but could be between the breaker and the table, or the breaker itself could be elastic. But the form shown is the simplest. and it protects the teeth of the cutters, which, in the case of teeth intended to dig sott, abrasive material, are comparatively delicate and lose their efliciency if damaged.

Having described iny invention, I claim:

1. In a breaker for drill bits, a plate with outside edges adapted to engage the rotary table and prevent rotation of the plate with respect to the. table, an opening in the plate adapted to receive a bit and prevent rotation of the bit with respect to the plate, a resilient pad mounted under the plate adapted to engage the bottom of said bit and hold it upright in cooperation with the .ppening or the plate, said pad being vertically and horizontally resilient, whereby the bit can move axially and pivot along a transverse axis under influence of the weight of and impacts by the drill collar.

2. A support for a bit to be used in attaching the bit to a drill collar including a basket shaped member, means preventing rotation of said member with respect to a table, means supporting said member with respect to the table, a resilient bottom in. said basket for supporting the bit, and rigid means above the bottom of the basket engaging the sides of the bit to prevent lateral displacement of the bit at that point, whereby said bit is resiliently supported in an upright position for engagement with the drill collar.

3. A support for a bit to be used in attaching the bit to a drill collar, including a portion adapted to engage a rotary table, a portion adapted to engage'the bit, both of said portions cooperating to prevent rotation of the bit with respect to the table, and resilient means engaging the bottom of the bit, said last mentioned means being resilient under the weight of a drill collar. 3

4. A support for a bit to be usedin attaching the bit to a drill collar, including a portion adapted to engage a rotary table, a portion adapted to engage the bit, both of said portions cooperating to prevent rotation of the bit with respect to the table, and resilient means engaga drill collar JOHN A. ZUBLIN.

4o ing' the cutting edges of the bit,.said last men- 

